In the last 20 years the prevalence of asthma has doubled and it now affects 10% of the population in the United States. The susceptibility to allergic asthma varies greatly in the population exposed to allergens. Gene-environment interaction may play an important role in pathogenesis of asthma. Our long-term objective is to understand the host factors that regulate susceptibility to allergens and the pathogenesis of asthma. Such an understanding is vital for developing new intervention strategies. We recently reported a novel host factor, nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), that may play a critical role in determining susceptibility to allergic asthma. Nrf2 is a basic leucine zipper transcription factor that determines the severity to asthma in mice models by regulating environmental stress response that includes cellular antioxidants. Disruption of Nrf2 in mice leads to severe asthma in response to sensitization and challenge by variety of allergens such as ovalbumin and ragweed extract. The exaggerated asthmatic response in Nrf2-disrupted mice in response to allergen involves increased oxidative stress and pronounced infiltration of eosinophils into the lungs, greater T helper 2 cells and cytokines (IL-4, IL-13), antigen-specific IgE, mucus cell hyperplasia, airway hyperresponsiveness. Thus, Nrf2 is a critical regulator of asthma pathogenesis.Our central hypothesis is that Nrf2 dependent compensatory transcriptional program regulate the environmental stress response that protects against allergen-induced asthma by decreasing oxidative stress in the airway epithelium and Th2 effector cells that in turn inhibits cytokine and chemokine expression. Conversely, disrupted or suboptimal Nrf2 activity causes increased oxidative stress and asthmatic response. Specific Aim 1: To investigate the regulation of asthma by Nrf2 activity in the airway epithelium. Specific Aim 2: To investigate the regulation of asthma by Nrf2 activity in T effector cells. Specific aim 3: To test the hypothesis that genetic variation in Nrf2 and its target antioxidant genes is associated with susceptibility to childhood asthma and atopy.Specific Aim 4: To test the hypothesis that enhancing Nrf2 activity can attenuate asthma.The proposal will focus on investigating Nrf2 dependent regulation of asthma pathogenesis and strive to develop a preclinical intervention strategy by targeting this transcription factor for decreasing asthma in the susceptible individuals in the population.